Muffler for internal combustion motors



June 2, 1964 E. A. MATTlE 3,135,350

MUFFLER FOR INTERNAL COMBUSTION MOTORS Filed Jan. 6, 1961 .5 Sheets-Sheet 1 42 451 El E1 INVENTOR.

EUGENE A. MATTlE BY ATTORNEYS 3 Sheets-g 2 INVENTOR. I EUGENE A MATTE BY M (Q/Uw ATTORNEYS June 1964 E. A. MATTIE MUFFLER FOR INTERNAL COMBUSTION MOTORS Filed Jan. 6, 1961 June 2, 1964 E. A. MATTIE 3,

MUFFLER FOR INTERNAL COMBUSTION MOTORS Filed Jan. 6, 1961 E s Sheets-Sheet s INVENTOR.

EUGENE A. MATTIE ATTORNEYS This invention relates to a muffler for the exhaust from combustion motors, an object of the invention being to provide a structure which -i's-relatively small in volume and eifective in noise-suppression as compared with prior United StatesPatent Office one with which the broad end 28 is merged. The outer edge 30 of each blade 24 fits against the inner-surface v of the tubular casing 10. Each blade has an arcuate free muffiers, but with no additional increase in the backpressure resulting fromjits use. The muffler hereinafter described has been found to operate in a highly satisfactory manner. Itcan also be cast in two parts of identical form in which there are no smallpassages subject to being clogged by sootyor dirt. I Other advantageous features will be apparent from-the following description thereof and from the drawings, of which I i f FIGURE 1 is a plan view of a mufiier embodying the invention; g O FIGUREfZ is aside elevation of .the same;

FIGURE 3 is 'a cross-section, 'on -a larger scale, on the line 3 -3 of FIGURE 4, but of a complete muffler; I 1

FIGURE 4 is a plan view, on a larger scale, of one of the two parts of the muffler shown in FIGURES 1 and 2;

FIGURE 5 shows the diagram which would be formed by inking the edges of. the. blades of one cylindrical unit of the mufiler and rollingthe unit onceon a plain sheet of paper;

FIGURE 6 is a fragmentary perspective view of blade structure within one cylindrical unit of the muifler;

FIGURE 7 is a perspective view of the same in another angular position; and

FIGURE 8 is a fragmentary perspective view of the same in still another angular position.

The muffler hereinafter described consists of one or more tubular units 10 in each of which is located a baflle structure 12 of novel design. One or more such units may be employed, two being shown in parallel in FIG- URES 1 to 4. The baffie structure for a single unit is illustratedin FIGURES'G, 7 and 8. This structure may be fitted into but removable from a tubular casing, or it may be formed in identical halves whichmay be assembled in a one-piece or two-piece tubular casing 16 or maybe integrally cast with semi-cylindrical casing parts 16 as indicated in FIGURE 3. When tw0-such semicylinders 16' are secured together they form a complete mufiier. For convenience, the baffle structure will be described separately, as illustrated in FIGURES 6, 7 and 8.

The bafile comprises a central axial stem 20 which is preferably rectangular in cross-section, the width being twice the thickness. A series of diametral ribs 22, 23 are of curved blades 24 each of which is cylindrically curved about an axis which is transverse with respect to the axis of the casing. Each blade 24 subtends an arc of about 90 so that one end 26 of each blade is nearly tangent to a plane parallel to the axis of the casing while the other end 28 of the blade is'tangent to a transverse plane.

Each blade 24 has preferably the same thickness as the stem 20 or ribs 22, 23, so that the end portion 28 merges laterally with one ofthe ribs 23, the narrow end 26 being secured to or integral with an end of the'rib next to the inner edge 32 which extends from one rib 22 to the next rib 23 and lies in the plane defined by the adjacent edges of the stem and ribs; The blades inone half of the casing all curve in the same sense, the blades in the other half curving in the opposite sense, so that the 'appear-. anceof the bafile 12 is thesame when viewed from'either end. Each rib 23 merges at one side edge with :a blade 24 of one series and at the other side edge .witha blade 24 of the others'eries. Likewise, the outer. end portion .of each rib 22 is joined by end portions 26 of a rib from both series. To reinforce this joint and, fill inthe small space between the narrower ends 26 nof the-blades V and the inner surface of the casing, a transverse segment 36 is provided integral witheach pair of blade ends 26 and the end of the rib '22 between them. 1 The outer edges of the blades 24 and segments 36 form anirregular double helix which is developed on a plane in FIG- URE 5 of the drawings.- The edge of each-segment 36 is inclined slightly from a transverse plane. From either end of the segment the edge 30jof a blade 24'curves'sharply through an'arc of about 90" the'n'flattens to an almost .straightsection which represents the outer edges of the wide end portions 28of a pair of blades -24which merge "with thesame rib 23. Y

The number of blades in each series in a tubular casing may be varied, but twelve such blades'in each series has been found to be desirable, that number being shown in each series in FIGURE 4. The size andcertain dimensions of a muffier will vary according to the size and number of cylinders of the motor with which the mufiler is used. The following table gives preferred dimensions for mufflers used with small one-cylinder or two-cylinder motors such as areused on lawn mowers, or as outboard marine motors, for four-cylinder motors such as are used in many small automobiles, and for six-cylin der and eight-cylinder motors such-as are used in larger automobiles.

N =number of motor cylinders D=interior diameter of the tubular easing d=pitch length, i.e., the axial distance between successive ribs a=width of the stem or a rib b=thickness of the stem or a rib Measurements are given in inches.

The bafile structure shown in FIGURES 6, 7 and 8 has been described as a separate article. By making it in two parts such as would be formed by cutting the article by an axial plane bisecting the stem 20 and all the ribs 22, each half can be conveniently cast integrally with a semicylindrical half of the tubular casing.

Such a casting of half of a double unit is illustrated in FIGURE 4. Two semi-cylinders 16 with separate baffles therein or 16' with integral semi-bafiies are joined by a common flange 40 along their mutually adjacent side edges, flanges42, 44 being provided along the mutually remote side edges. These flanges have faces in a common plane so that two castings can be bolted together to form a complete mufiler, bolt holes 46 being provided for that purpose. At each end of, the semi-cylinders is an extension 50 in the form of a Y-trough with rims 52 flush with the flanges 40, 42, 44. When two castings are bolted together, the troughs join to form Y-passages ,to and from the tubular casings. The castings are identical in every detail, one of them being reversed end-for-end be fore being bolted to the other.

Patented June 2,-1964 Within each'semi-cyhnder'16' and integrally cast therewith are elements similar to those hereinbefore described as elements of a haflle structure 12. A stem 20' extends along the axis of each semi-cylinder, this stem being intersected by a uniformly spaced series of diametral ribs 22', 23'. The stem ribs are flush with the flange-40, 42, 44 and the rims 52. The stem 20' and ribs 22', 23 being halves of corresponding stem 20 and ribs 22, 23, have square cross-sections. In each'semi-cylinder 16' is a series of blades 24' which are shaped and arranged with respect to the stem 20' and ribs 22', 23, exactly like the arrangement of one of the series of blades 24 of the baflie structure shown in FIGURES 6, '7 and 8. Thus when two the curved bafiles, said loops having an axis which is perpendicular to the longitudinal axis of the housing.

1. A mufller for the exhaust'from an internal combustion motor, comprising two halves of identical form secured together, each said half comprising asemi-cylindr'ical casing part, an axial stem in said casing part, a series of arcuately curved blades disposed in each half "with an" edge thereof abutting the inner surface of the semi-cylinder, each said blade having a broad end portion 1 4 a t disposed in a transverse plane which is perpendicular to the axis of the semi-cylinder, the other end of each blade being narrower and at a steep angle to a transverse plane.

2. A muflier for the exhaust of an internal combustion motor, comprising two halves of identical form secured together, each'said half beinga unitary structure comprising two semi-cylinders joined side-by-side by a common flange, a flange along the other side edge of each semi-cylinder in the same plane with said common flange, an extension at each end of said semi-cylinders forming a Y-trough branching to the semi-cylinders, each said'semicylinder having therein an axial stem, uniformly spaced radial ribs projecting from said stem, said stem and ribs being flush with said. flanges, and a series of arcuately curved blades in each said semi-cylinder, each saidblade having an edge thereofintegral with, the inner surface of the semi-cylinder in which it is located, each said blade having a broad end portion disposed in a transverse plane which, is perpendicular to the axis of the semi-cylinder,

the other end of each blade being narrower and at asteep angle to a transverse plane, each said blade having a free edge portion substantially in a plane defined by the edges of said semi-cylinders.

References Citedin the fileof this patent UNITED STATES PATENTS 1 1,236,987 Schmitt Aug. 14, 1917 1,695,375 Heather Dec. 18, 1928 2,707,525 Janeway lMay 3, 1955 FOREIGN PATENTS 7 242,743 Great Britain Nov. 19, 1925 303,997 1 Great Britain Ian. 17, 1929 

1. A MUFFLER FOR THE EXHAUST FROM AN INTERNAL COMBUSTION MOTOR, COMPRISING TWO HALVES OF IDENTICAL FORM SECURED TOGETHER, EACH SAID HALF COMPRISING A SEMI-CYLINDRICAL CASING PART, AN AXIAL STEM IN SAID CASING PART, A SERIES OF ARCUATELY CURVED BLADES DISPOSED IN EACH HALF WITH AN EDGE THEREOF ABUTTING THE INNER SURFACE OF THE SEMI-CYLINDER, EACH SAID BLADE HAVING A BROAD END PORTION DISPOSED IN A TRANSVERSE PLANE WHICH IS PERPENDICULAR TO THE AXIS OF THE SEMI-CYLINDER, THE OTHER END OF EACH BLADE BEING NARROWER AND AT A STEEP ANGLE TO A TRANSVERSE PLANE. 